The technique disclosed herein relates to a toothed belt, a production method therefor, and a belt transmission device.
In recent years, there has been a need for office automation equipment, information-processing equipment, household appliances, and other general industrial devices to be downsized, to be reduced in cost by simplifying their mechanisms by fixing the distance between shafts, and to consume less power. To satisfy this need, there has been an increasing demand that belts be operable with small pulleys, be assembled in a smaller number of steps, and reduce energy losses.
For example, Japanese Examined Utility Model Publication No. H01-39952 discloses a toothed belt which includes an elastic knitted fabric used as a tension member and which is made of a polyurethane elastic material. In this toothed belt, the tension member (the core) is embedded such that its stretch direction is parallel to the longitudinal direction of the belt. Therefore, even if the distance between pulley-mounting shafts is fixed, the belt can be meshed with the pulleys smoothly.
The known toothed belt of Japanese Examined Utility Model Publication No. H01-39952 is made in the following manner: a ring-shaped knitted fabric, which has been made by cutting a circular knitted fabric into rings, is made to cover the peripheral surface of a toothed inner mold, and an outer mold is concentrically set to surround the inner mold. Then, liquid urethane resin is injected into the cavity, and the molds are heated to cure the injected resin. Thereafter, the resultant belt molding having a cylindrical shape is removed from the molds, and cut into rings having a predetermined width, thereby making the toothed belt.